Technical Field
The present invention relates to data transport, and more particularly, to data transport using reconfigurable and variable-rate shared flexible Ethernet transponder architecture.
Description of the Related Art
While originally designed for use in Local Area Networks (LAN), the Ethernet protocol specified with the IEEE 802.3 Ethernet Working Group has been significantly extended in scope in recent years. The main reason for that is the ubiquity of Ethernet and the resulting economies of scale for the associated interfaces and equipment (e.g. switches). Furthermore, using the same protocol throughout the network facilitates the interconnection with clients, since Ethernet is the dominant technology in the access and aggregation part of the network. As a result, a large number of Metropolitan Area Network MAN) deployments have already appeared which use either pure Ethernet or Multi-Protocol Label Switching (MPLS) over Ethernet for communication among their nodes, while some service providers could even deploy such networks from their long haul optical packet transport all the way to the aggregation and access segments. Of particular importance are also inter- and intra-data center networks, whereby very large amounts of data are distributed in a bursty manner, making Ethernet a very attractive option due to its packet-based nature.
In order to address the increased overall user traffic requirements, and especially under the prism of the aforementioned developments, the IEEE has been continuously standardizing updates of the Ethernet protocol to support higher rates. The current IEEE 802.3ba standard defines 40 Gb/s and 100 Gb/s rates. In both cases, a multi lane approach is followed, whereby the Ethernet, electrical bit-serial signal is split into multiple parallel lower-rate electrical lanes for performing most of the electrical processing, which are then bit-multiplexed into a smaller or equal number of electrical lanes that are fed to an optical transceiver. The latter can also perform further bit multiplexing, depending, on the number of physical (PRY) lanes it employs. The next generation of Ethernet beyond 100G is also expected to follow a multi-lane approach (in both electrical and optical domains) mainly due to inherent limitations in state-of-the-art electronic processing capabilities as well as single-carrier optical transmission at such high rates.
Despite the ever increasing flexibility at the line side of optical networks (for example via the use of Orthogonal Frequency Division Multiplexing (OFDM) and Nyquist Wavelength Division Multiplexing (WDM) technologies), the current case is that transponders providing the interconnection with Ethernet clients at the edge of the network would produce fixed rate signals at one of the standardized Ethernet rates. The fact that Ethernet rates are defined in a step-wise fashion (i.e., 10 Gb/s, 40 Gb/s, 100 Gb/s) makes this inefficiency even worse. Since sufficient traffic aggregation cannot always be ensured, this mismatch is expected to result in spectrum waste at the optical network side.
Furthermore, energy efficiency has become a very crucial requirement in all types of networks, since it has to be ensured that power consumption will scale well with the rapidly increasing amounts of traffic that need to be carried over them. The transponders discussed above will still operate at the full line rate, even when the actual client traffic they handle is lower, thus unnecessarily consuming energy for the electronic circuitry implementing the protocol and the accompanying transceiver modules. Furthermore, for each Ethernet, signal that needs to be sent at the edge of the network towards there should be a separate line side port. This implies additional cost and power consumption at disproportionate levels compared to the actual amount of traffic that needs to be transferred.
It is noted that the Software-Defined Networking (SDN) concept, which has emerged in recent years, allows separating the data and the control planes. In the context of as transport network controlled in an SDN manner, the benefits are multifold and include the reduction of manual processes across domains and layers, the possibility for cross-layer optimization schemes, faster connection establishment and teardown, reduction of overprovisioning and simplified management.
As discussed above, there are currently issues with, and there is to need for efficiently deploying Ethernet as a transport technology in high-capacity and flexible optical networks, including rate flexibility, energy efficiency, cost and spectrum utilization, and efficient network control and management; and there is presently no solution which addresses these issues effectively.